1. Field of the Invention
The present invention relates to an apparatus for separating liquid droplets from a fluid flow containing the liquid droplets entrained therein. In particular, the invention relates to separating liquid droplets from a fluid flow by directing the fluid flow onto a rotating element, gathering the liquid droplets at a radial perimeter of the rotating element and collecting the liquid droplets therefrom.
2. Description of Related Art
Various devices are known for separating liquid droplets from a fluid flow. A fluid mixture may be generated that includes various components in a plurality of states, e.g. gases, vapors, liquids, liquid droplets and solid particles. Devices are known for separated or filtering fluid mixtures to remove a component from the main fluid flow. It is known to separate liquid droplets from a predominantly gaseous fluid flow by causing the fluid flow to rotate. By generating a rotation within the fluid flow, e.g. causing the fluid to rotate about the longitudinal axis of a cylindrical fluid conduit, a centrifugal force generated within the fluid flow causes liquid droplets to move toward a radial perimeter of the fluid conduit. The fluid flow is then divided by dividing the fluid conduit into a center portion, which receives a predominately gaseous component of the fluid flow, and a radial perimeter portion which receives the majority of the liquid droplets contained within the fluid flow. Accordingly, liquid droplets are removed from the main fluid flow, which continues to flow through the center portion. Examples of devices that utilize centrifugal force to separate liquid droplets from a fluid flow are disclosed in U.S. Pat. No. 6,190,438, by Rodgers et al., in U.S. Pat. No. 6,190,438, by Parks, and in U.S. Pat. No. 4,361,490, by Saget. While the above listed patent disclosures provide useful teachings for utilizing a centrifugal force to separate liquid droplets from a fluid flow, they do not provide a suitable solution to the problem of gathering the liquid droplets together and collecting the gathered liquid droplets for reuse. There is a need in the art, and especially in the art of fuel cells, to separate liquid droplets from a fluid flow, and a further need to collect the liquid droplets for reuse.
Fuel cell systems provide a portable and convenient way to generate electrical current by reacting chemical compounds, or reactants, in such a way a chemical reaction frees electrons for generating an electrical current that is usable for powering electronic devices. Generally, a fuel cell system includes one or more reactant source containers capable of delivering a continuous supply of each reactant to a fuel cell element. In some cases a reactant may comprise air or water which may be readily available from outside the fuel cell system. In any event, reactants may comprise liquids, solids, gases or a mixture thereof.
Generally, reactants are combined within a fuel cell element to generate an electrical current. A byproduct outflow is also produced. The byproduct outflow may comprise unused reactants plus other compounds and or solutions produced by the chemical reaction used to generate electrical current. Accordingly, the byproduct outflow may comprise liquids, solids, gases or a mixture thereof. There is a need in the fuel cell art to separate a byproduct outflow into component parts and to recover compounds and or elements from the byproduct that may be useful. Alternately hazardous compounds and or elements may need to be separated from the byproduct for proper handling. In particular, separating liquids from the outflow of a fuel cell is an important aspect of developing fuel cells, and especially separating liquid water from the byproduct outflow. In many fuel cell devices, a supply of liquid water is needed for various reasons, e.g. to hydrate an electrolyte (e.g., a solid polymer electrolyte), to dilute a reactant (e.g., to reduce reactant crossover), or for use in hydrogen gas production such as by reformation, or hydrolysis of a chemical hydride. In an effort to decrease the overall volume and weight of a fuel cell system, it is advantageous to separate liquid water from the byproduct outflow and to recycle it. In other instances, liquid water generated by a fuel cell must be collected and properly stored in order to avoid damage to the local environment of the fuel cell.
Water recycling schemes for fuel cell systems are disclosed in numerous U.S. patents including U.S. Pat. No. 6,436,562 by DuBose, U.S. Pat. No. 6,436,563 by Frank et al., U.S. Pat. No. 6,921,601 by Senner et al., U.S. Pat. No. 6,893,754 by Agar et al., U.S. Pat. No. 6,950,729 by Michell et al., U.S. Pat. No. 6,447,945 by Streckert et al., and U.S. Pat. No. 5,064,732 by Meyer. These patents collectively disclose various device and process elements used to separate liquid water from the outflow of a fuel cell. However, the prior art water recovery systems are complex and add undesired weight, volume and cost to the fuel cell system. Moreover, most of the water managements systems disclosed in the prior art utilize electrical pumps and or motors to manage the liquid water and these electrical devices reduce the overall efficiency of the fuel cell system.
Accordingly, there is a need in the fuel cell art for a simple device for separating liquid droplets, especially water, from the byproduct outflow and for collecting the liquid droplets. Moreover, there is a need in the fuel cell art to reduce the volume, weight, cost and electrical energy consumption of liquid and or water management systems. There is a still further need in the fuel cell art for a liquid and or water management systems that can operate in al possible orientations without degrading the performance of the fuel cell system.